Morphing swiftly from YouTube sensation to international phenom, power-pop prince Justin Bieber is charting his next career move: movie star.

It's a steamy Friday afternoon in July, and Justin Bieber sightings are rippling through downtown Memphis. A group of girls spot him skateboarding with friends on Beale Street. An enthusiastic local catches a blurry photo of him getting off his bus. Packs of young women camp out in the lobby of the Westin hotel where he and his entourage are staying. The Memphis blues are momentarily cured, but Bieber fever is raging.

The true Beliebers are fearless—and not just in this particular city. In Portland, Oregon, they were willing to scale tall buildings the afternoon of Teen Vogue's cover shoot; in Phoenix they ran him down while he was on his Segway in a parking lot. Back in April a rabid gang of New Zealanders nearly trampled his mother and stole his prized purple baseball cap as he was leaving the airport.

To be fair, tracking down Justin on tour isn't hard—he hasn't yet reached his "reclusive" stage. If anything, he wants to be out in the real world more (a fact that doesn't please his bodyguard Kenny). When I sit down to talk with the Ontario native in his green room at the FedEx Forum, he confirms that he spends as much time as possible "being real": hanging with his friends; skateboarding; messing around on the Internet; and on the rare mornings he's able to do so, sleeping in. Today the sixteen-year-old is on vocal rest—the result of performing for 23 of the past 39 nights— and is talking softly, sitting across from his manager, Scooter Braun.

Things have changed for Justin since he began uploading videos of his covers of popular songs like Alicia Keys's "Fallin' " to YouTube in 2007. After the clips went viral, he was quickly signed to Island Records, and in May 2009 he released his first single, "One Time." In November his debut album, My World, came out and went platinum in two months. Since its release (and the subsequent My World 2.0), Justin's life has been nonstop. But the tour isn't even halfway done, and the girls— well, their numbers grow exponentially at every stop, especially as the young star's voice deepens and he transitions, say his devotees, from "little boy" to "oh, boy."

His fans certainly aren't too shy to talk to him when they spot him on the street. "No girls are nervous," he says. But the right way, he advises, to approach him is as follows: "Just talk to me. Ask me how I'm doing. Introduce yourself instead of yelling, 'Justin! Justin! Justin! Can I have a picture?' And don't come up to me while I'm eating. How would you like it if I came into your house and started taking pictures of you while you were eating? I hate that."

He makes a valid point, but it's like pouring a bottle of water on a forest fire. The amount of fame Justin has attained is so massive, at times it seems to almost overwhelm him. "It's still amazing to see people wearing my shirts," he says. "But I feel like I can't get away from myself. Like, I go to Walmart and I just want to go get some bors and socks, but there are posters of me everywhere. Or my song comes on the radio, and it's like, 'Aah!'" As his accelerated career continues to develop, he's now looking at a specific path that will help him escape being "Justin Bieber." He's ready to go Hollywood.

Justin's fresh off shooting the first episode of his prime-time acting debut—a role on CSI in which he plays a "badass" named Jason McCann in the two-episode arc of the CBS crime drama (the first episode airs September 23; the second will bow next February). "It seems like I'm this sweet and innocent kid, and then it turns out I'm the mastermind behind everything," he reveals of his character—before Scooter jumps in to stop him from spoiling any more. To prepare for the role, Justin met with an acting coach for the first time ever. "She told me it was all about the emotion," he says. "She said, 'You have to feel the character. You have to be Jason.' " The coach even had him focus on his sad memories. But, he says, "I think I would have done it the same whether I channeled my feelings or not." Still, he was encouraged by the experience and is insistent about his ambition to build up to meatier roles in the coming months. (Scooter later mentions that there are plans for the acting coach to join the My World tour later this fall to start regular sessions with Justin.)

His confidence in his own acting skills isn't the sign of an inflated ego—he's naturally restless. And not just when he's on tour (where he sings, dances, and drums every night) or stealing the show on Saturday Night Live (last April he played against Tina Fey as if he'd studied at Second City)—all the time. When Justin tells a story about Lil Wayne, he is Weezy, complete with stage posturing (read: crotch grabs). If he's talking about drumming, he hits imaginary high hats. Even in the moments when he's discussing something personal or sensitive, he stands, crumpling a water bottle or kicking things that are lying around the room.

"I want to be the lead star in a movie. Can we make that happen, Scooter?" he asks.

"I think everyone wants that," his manager replies cautiously.

"Yo, but why don't we do it . . . soon?" Justin asks, staring him straight in the eye.

He's got many "top-secret" roles in the works. Scooter later tells me that the biggest thing on the horizon for Team Bieber is a feature that will be produced by Will Smith and his company, Overbrook. Justin met the blockbuster actor and his son Jaden during the recording of "Never Say Never," the theme song for this year's The Karate Kid remake. The two camps are in talks to move forward with a starring vehicle for Justin—not his own 8 Mile, Scooter clarifies, just a fictional piece that may have some similarities to Justin's life. The film is likely to begin production next spring or summer.

Before that, though, there's a different project set in stone: Justin's August 31 concert at New York's Madison Square Garden will be filmed for a 3-D concert-movie-slash-documentary that will see a theatrical release on Valentine's Day weekend, 2011. The MSG show is set to take place almost a year to the day after Justin was invited to see one of his biggest supporters, Taylor Swift, perform there in 2009. The country superstar shined a spotlight on the not-quite-yet-a-phenomenon singer in the crowd and dedicated a song to him. Less than a year later, Justin sold out the same venue in 22 minutes.

That's not the only thing on his agenda, however—he's on tour until the end of December and will be releasing a photo biography, published by HarperCollins, this month. There are also plans to put out a repackaged version of My World with new songs next year. But even though his big-screen debut is further down the pike, Justin is inspired by all the possibilities. At the suggestion of a romantic comedy, he's quick to propose a potential love interest: "Selena Gomez." When Scooter accuses him of "starting a fire," Justin smiles hugely. "She's a good buddy of mine," he counters. "She's really nice."

Though his energy has been flagging, Justin perks up when talking about Selena and his future career. "We should shoot a movie in January or February of next year," he announces to Scooter. "I want to shoot a movie." His manager isn't hearing it. There's touring to be done in South America first. Oh, well.

And with that, Justin must make his exit. Still nursing strained vocal cords, he's got some hot tea to drink and a humidifier to snuggle up to before hitting the stage to perform in front of 18,000 screaming members of Bieber nation. Someday soon he'll be selling out multiples. But right now, he's Justin Bieber, singer. And his fans are waiting.

Edited for teenvogue.com. For the complete story pick up the October 2010 issue of Teen Vogue, on newsstands September 14!